Aggregate pumping apparatus



Nov. 4, 1969 Filed Sept. 8, 196'? P. W. MCELROY AGGREGATE PUMPINGAPPARATUS 2 Sheets-Sheet 1 F|G.I

52 HYDRAULIC PRESSURE SYSTEM l2 L' "g Y l 2 J INVENTOR.

Y PHILIP VLMC ELROY Nov. 4, 1969 P, w. MGELROY AGGREGATE PUMPINGAPPARATUS 2 Sheets-Sheet 2 INVENTOR.

PHILIP W. MC ELROY www ATTORNEYS United States Patent O 3,476,057AGGREGATE PUMPING APPARATUS Philip W. McElroy, 2300 Dolores Court,Pinole, Calif. 94564 Filed Sept. 8, 1967, Ser. No. 666,442 Int. Cl. F04b.Z9/04, 1/00; F15b 11/20 U.S. Cl. 103--167 4 Claims ABSTRACT F THEDISCLOSURE This invention relates to apparatus for pumping denseaggregates such as concrete aggregate.

Because of the high abrasive character of concrete aggregate, pumpsadapted for handling such aggregate must be of simple and ruggedconstruction. A pump according to the present invention provides suchconstruction.

The essential elements of a concrete pump according to the presentinvention are a concrete hopper having a discharge outlet at the bottom,a piston chamber that supports a piston therein for reciprocal movementto `draw aggregate into and expel aggregate from the chamber, and avalve controllably interconnecting the concrete hopper and the pistonchamber so that in one phase of operation, concrete is transferred fromthe hopper into the piston chamber and in a second phase of operation,concrete is discharged from the piston chamber through an outlet in thevalve.

An important object of the present invention is to provide a valveoperable as described above that is of simple long-wearing constructionand which requires only minimum power. Power required for operating thevalve is minimized by providing a valve gate plate that is curved todene a segment of a cylindric surface and by actuating the gate platearound the central axis of such cylindric surface so that the platemoves transversely of the direction of concrete ow. Such direction ofgate plate movement requires a minimum amount of power because movementin such direction renders unnecessary overcoming the pressure of theconcrete.

Further contributing to the simplicity of the present invention is avalve housing in which the above described gate plate is supported. Thehousing has three passages therein that extend radially of the cylindricaxis. With the first of these openings is associated the piston chamber;with the second of these openings is associated the concrete hopper. Thethird opening is the concrete discharge opening. The gate plate isrotatably movable so as to close either the concrete hopper opening orthe discharge opening. Thus, 'the piston chamber communi cates with theaggregate hopper during its loading stroke and with the dischargeopening during its discharge stroke.

The present invention also includes in combination with the hopperpiston chamber and valve described above, a second piston chamber thathas a displacement volume equal to one-half the previously mentionedpiston chamber. Such combination affords a continuous ow of concrete byoperating to load the secondary piston chamber during the dischargestroke of the primary piston chamber and to discharge the secondarychamber into an outlet line while the primary chamber is being chargedfrom the hopper. Thus, a steady discharge is achieved withoutcomplicated structures.

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Another aspect of the invention resides in an improved hydraulic controlsystem for controlling the valve and the primary and secondary pistonsin proper timed relation.

The foregoing as well as other objects, features and advantages of thepresent invention will become more apparent after referring to thefollowing specification and accompanying drawings in which:

FIG. 1 is a plan view of the apparatus of this invention, portions beingbroken away to reveal internal details thereof;

FIG. 2 is an elevation view taken along line 2 2 of FIG. l;

FIG. 3 is a transverse cross section in elevation taken along line 3-3,of FIG. 2;

FIG. 4 is a perspective view of the valve gate plate of the presentinvention; and

FIG. 5 is a partially schematic view of the hydraulic control system ofthe present invention.

Referring more particularly to the drawing, reference numeral 12indicates a primary piston chamber mounted on a frame member 13. Pistonchamber 12 supports a piston or plunger 14 which is reciprocally drivenwithin the chamber in a charge stroke and a discharge stroke by a rod16. Piston chamber 12 is attached to a valve housing `18, the valvedefining a cylindric cavity 20 with which the interior of piston chamber12 communicates through a port 22.

Also secured to valve body 18 is a concrete hopper fragmentarilyindicated at 24 which communicates to cavity 20 through an opening 26.Valve body 18 finally includes a discharge port 28 which communicates toan outlet pipe tting 30.

Supported interior of valve casing 18 is a valve 'body assemblydesignated generally by reference numeral 34 in FIGURE 4. The assemblyincludes a curved gate plate 36 that forms a segment of a cylinder. Thegate plate is mounted at its ends to two circular end members 38 and 40.Stub shafts 42 and 44 are respectively secured centrally of circularplates 38 and 40.

Valve housing 18 is bushed at 46 and 48 to respectively support forrotation stub shafts 42 and 44, so that gate plate 36 is concentric withthe surface of cavity 20. The valve assembly 34 is movable between aposition at which gate plate 36 closes port 26 (see FIG. 2) and aposition at which the gate plate overlies outlet port 28 (indicated bybroken lines in FIG. 2). A lever arm 50 is attached to shaft 42 toeffect such movement of the gate plate, a hydraulic cylinder 52 having arod 54 connected to lever arm 50 being provided to so drive the leverarm.

Outlet pipe fitting 30 defines one leg of a Y tting 56 which has anoutlet pipe 58 and a branch 60. Branch 60 is attached to a secondarypiston chamber 62 which is mounted on frame 13 generally parallel withprimary chamber 12. Secondary piston chamber 62 supports interiorthereof a piston or plunger 64 which is driven through a dischargestroke and a charging stroke by a piston rod 66. Secondary pistonchamber 62 has a crosssectional area equal to one-half thecross-sectional area of piston chamber 12 so that when piston -64 movesan amount equal to the movement of piston 14 the displacement fromchamber 62 is one-half that of chamber 12. In one pump designedaccording to the present invention a piston 12 having an inside diameterof 11% inches was used with a chamber 62 having an inside diameter of 8inches.

The operation of my improved valve and pump can be understood byassuming that hopper 24 is full of concrete aggregate and that gateplate 36 is in the position shown by solid lines in FIG. 2. Piston 14 isat the beginning of the charging stroke in chamber 12, that is, the

piston is at its left extremity of movement as viewed in the figure.First, hydraulic cylinder 52 is energized to move gate plate 36 in acounter-clockwise direction to the broken line position as viewed inFIG. 2, simultaneously with which piston 14 is moved rightwardly byhydraulic systems to be described hereinbelow. Concrete aggregate enterscavity 20 by gravity and is drawn into chamber 12 as piston 14 movesrightwardly in its charging stroke. Simultaneously, with such movement,piston 64 moves in a discharge stroke within chamber 62 that is, piston64 moves leftwardly as seen in FIG. 1. When piston 14 has completed itscharging strokes so that chamber 12 is iilled with aggregate, hydrauliccylinder 52 is again actuated to move the valve assembly clockwise asviewed in FIG. 2 so that gate plate 36 closes port 26 and opens port 28.Such movement of the gate plate takes relatively little power since thegate is moving in a direction transverse to the direction of concreteow. Also, minimizing the power necessary to close the gate is a bevelindicated at 67 in FIG. 2 that is formed on the edges of gate plate 36.Movement of the gate plate to a position closing port 26 inhibitsfurther delivery of concrete from hopper 24. On leftward movement ofpiston 14 through a discharge stroke, aggregate is moved leftwardly asviewed in the figure through port 28 and into conduit 30. Becausesubstantial resistance exists downstream of outlet pipe 58, some of theaggregate will flow into branch 60. Moreover, movement of piston 64rightwardly in chamber 60 draws the aggregate into chamber 62. Becausechamber 62 has a displacement equal to one-half that of chamber 12,one-half of the aggregate discharged from chamber 12 is conveyed outthrough pipe 58 and one-half is loaded into chamber 62. When pistons 14and `64 return to the positions shown in FIG. 1, gate plate 36 againmoves counterclockwise to close port 28. Piston 64 is then driven in adischarge stroke, leftwardly as viewed in the figure, so as to dischargethe contents of cylinder 62 through outlet conduit 58. Also occuring atthis time, as a consequence of rightward movement of piston 14, ischarging of cylinder 12 with aggregate from hopper 24. Thus, chamber 12is loaded for the next stroke, and the sequence of operations describedcontinues in alternation to deliver a continuous ow of concrete throughoutlet l58.

For efliciently operating pistons 14 and `64, a hydraulic actuator 68 isconnected in driving relation to rod 16 and a hydraulic actuator 70 isconnected in driving relation to rod 66. The operation and control ofthese actuators is shown in more detail in FIG. 5.

A piston 72 is mounted for reciprocating movement within actuator 68;piston 72 is attached to rod 16 which extends into actuator 68.Correspondingly, a piston 74 is attached to rod 66 and is disposed inactuator chamber 70 for reciprocating movement therein. The left or rodends of actuators 68 and 70 are connected to one another through a tube76. To the opposite end of actuator chamber `68 is connected a fluidline 78 which, through a solenoid valve 80, is selectively connected toa source of hydraulic iiuid under pressure `82 and a return reservoir84. On the opposite end of actuator chamber 70 a uid line 86 isconnected to a solenoid valve 88 which is also selectively connectableto pressure source 82 and hydraulic fluid return reservoir `84. Valves80 and 88 are operated in unison by an electro-magnetic solenoid coil90. The coil 90 is connected to a battery 92 through a double pole,double throw reversing switch 94. The moving contacts of the switch areoperatively associated with spaced apart discs 96 and 98 which discs aremounted on an actuator rod 100.

Actuator rod 100 is carried in a guide 102 in the end of actuatorchamber 68. The inner end of rod 100 is supported in a central bore 104of piston 72. Bore 104 has a reduced diameter portion 106 and rod 100`has an enlargement 108 which cooperate to move disc 96 leftwardly so asto effect reversal of switch 94 when piston 72 reaches its leftwardextremity of travel. When piston 72 reaches the rightward extremity ofits movement within actuator chamber 68, enlargement 110 on actuator rod100 is engaged by piston 72 so as to move disc 98 into contact with thereversing switch 94. Rod 16 is hollow so as to permit rightward movementof piston 72 without interference with actuator rod 100.

The operation of this portion of the hydraulic system can be understoodif it is assumed that pressurized hydraulic fluid is being deliveredthrough valve and fluid line 78 into actuator chamber 68 so as to drivepiston 72 leftwardly. AS the piston reaches its leftward extremity, aposition that it has just reached in FIG. 5, the disc 96 will move thearmature or moving arm of reversing switch 94 to the left and willenergize coil 90 so as to actuate valves 80 and 88. When valves 80 and88 are rotated in the direction of the respective arrows by about 45degrees, valve 80 connects fluid line 78 to return reservoir 84, andvalve 88 connects iiuid line 86 to pressurized iiuid source `82. Theconsequence of the latter actuation is that piston 74 will be moved tothe left and piston 72 will 'be moved to the right until the latterpiston encounters enlargment 110 and moves rod so that disc 98 reversesswitch 94 again. Thus, it will be seen that pistons 14 and 64 will bereciprocated so as to discharge concrete aggregate as described hereinabove.

It has been found that evenk the highest quality hydraulic piston oractuator has a certain amount of leakage which, if unCOmpanSated, wouldsoon permit the two pistons to operate out of the proper phase. Tocompensate for such leakage as may occur, piston 74 is provided with avalve assembly to assure proper cooperation of the pistons. Piston 74 isformed with a fluid passage 112 therethrough at the high pressure orright end of which is formed a chamfered seat that is normally closed bya valve 114. Valve 114 has a stern 116 that extends through passage 112;a compression spring 118 is mounted in circumscribing relation to thevalve stem for normally biasing valve 114 to a closed position. a lever119 pivotly mounted to rod 66 at 120 is attached at one end to valvestem 116 and at the other end to an actuator rod 122. Rod 122 extendsthrough a bore in piston 74 and extends beyond the face of the piston asat 124.

The operation of the uid leakage compensation system is as follows:

If a piston 74 is driven rightwardly as viewed in FIG. 5 by uid forcedthrough line 76 by leftward movement of piston 72 and such movement isexcessive, actuator rod end 124 will contact the right end wall ofactuator chamber 70 before reversing switch 94 is operated by disc 96.The consequence of such contact by rod end 124 is that lever 119 rocksto open valve 114 so as to permit uid to pass piston 74 without drivingthe piston. If pressurized fluid is now supplied to chamber 70 throughvalve 88 and line 86 (that is, on the right face of piston 74) and ifleakage past piston 72 occurs, piston 74 can reach the leftwardextremity of actuator chamber 70 before piston 72 urges disc 98 intocontact with the reversing switch 94. If such happens, the leftextremity of valve stem 116 contacts the left end wall of actuatorchamber 70 and forces valve 114 open against the force of spring 118.This permits Huid to bypass piston 74 until piston 72 moves rightwardlyby an amount suicient to effect reversal of switch 94. By a relativelyuncomplex valve structure hydraulic fluid leakage is compensated to theend that pistons 72 and 74 are in proper phase relation at all times.

It will thus be seen that the present invention provides yan improvedvalve for concrete aggregates, an improved pump system for pumpingconcrete aggregates, and an improved electro-hydraulic control systemfor such pump. Because of the relatively few simple moving parts in thesystem, extremely long trouble-free operation can be achieved.

Although one embodiment of the invention has been shown and described,it Will be obvious that other adaptations -and modifications can be madewithout departing from the true spirit and scope of the invention.

I claim:

1. Apparatus for pumping concrete aggregate comprising first and secondplunger chambers each having an outlet opening and iirst and secondplungers slidably supported in said chambers for reciprocal movementtowards respective said openings in a discharge stroke and away fromrespective said openings in a charge stroke, hydraulic actuators foractuating said plungers, each actuator comprising a cylinder, a pistonaxially movably disposed in the cylinder and rod means interconnecting aplunger and a piston, the apparatus further including iirst conduitmeans interconnecting end portions of the cylinders which are adjacentthe position of the pistons at the end of the respective dischargestrokes of the plungers, Iand valve means for maintaining the pistons inphase during the operation of the hydraulic actuators, the valve meansbeing mounted to one of said pistons and comprising a closure memberaxially movably mounted in a passage defined by said one piston, meansbiasing said closure member in a passage closing position, and meansmoving said closure member in a passage opening position when saidpiston approaches the re spective cylinder ends, whereby a prematurearrival of said one piston at one of said ends, relative to the positionof the other piston, causes the opening of a hydraulic fluid bypass bysaid closure member and prevents further movement of said one pistonuntil the fluid pressure acting thereon is reversed.

2. Apparatus according to claim 1 including second conduit meanscommunicating a source of pressurized iiuid with the end of saidcylinders opposite the ends thereof coupled by said first conduit means,control valve means disposed in said second conduit means foralternatingly coupling said source 'with one or the other of saidcylinders, solenoid means operating said control valve means, and asolenoid actuator comprising a rod coupled to one of said pistons,projecting past a cylinder end and including solenoid actuating membersdisposed on the portion of the rod projecting past said cylinder end.

3. Apparatus according to claim 2 wherein said solenoid actuating rodmoves over a distance substan- 6 tially less than the length of a workstroke of said one piston, wherein said one piston includes an axialbore axially movably mounting said rod, and wherein said rod includesspaced-apart rst and second piston engaging members for causing saidlimited axial movement of said solenoid actuating rod.

4. In an Iapparatus for pumping con-crete aggregate and having a pair ofreciprocating plungers slidably disposed in chambers for movement of theplungers in charge and discharge strokes, a hydraulic actuator foreachuof the plungers, the hydraulic actuators including axially movablepistons disposed in cylinders, and control means for alternatinglypressurizing one or the other side of the pistons, the improvementcomprising: valve means mounted to at least one of the pistons andhaving a closure member positioned to close a passageway iiuidlycommunicating portions of the cylinder disposed on each side of the onepiston;

means for biasing the closure member in a passage closing position, andmeans acting in opposition to the biasing means for moving the closuremember into its passage opening position in response to an out-of-phaserelationship between the pistons, lwhereby a uid pressure build-up inthe pressurized por- 'tion of the cylinder due to an out-ofJphasemovement of the one piston disposed in the cylinder is prevented andpressurized fluid is permitted to drain through the passageway to theunpressurized portion of the cylinder until the pistons are in phaseagain.

References Cited UNITED STATES PATENTS 2/ 1942 Vickers 103-49 9/ 1945Longenecker.

l/ 1946 Fitzgerald.

12/1961 Shimatanl et al. 10/1962 Handl 103-167 FOREIGN PATENTS 131,2172/1949 Australia.

HENRY F. RADUAZO, Primary Examiner U.S. C1. X.R.

